This is a "Center's Grant" providing core support to the Center for Demography and Ecology at the University of Wisconsin-Madison. The major resource funded by this grant is a data processing facility devoted to the processing of Census tapes. Approximately 32 staff researchers, many with projects funded from other sources, and over 30 graduate students are associated with the Center and make use of these facilities. Among the project currently in progress at the Center are studies of fertility, residential segregation, changing population distribution, marital disruption, labor force behavior, occupational mobility, income differentials, and migration.